1. Field of the Invention
The present invention relates to a device for the detection of ignition/misfire in an internal combustion engine for use in an automotive vehicle. This ignition/misfire detection is beneficial in that it detects the boundary between ignition and misfire, i.e., ignition limits, thereby enabling the operation of an engine at an optimum condition.
2. Description of the Prior Art
If a method could be found for detecting the ignition limits of an engine, it would enable control of the air-fuel ratio, the EGR, or the ignition timing of an engine to be much improved. For example, if the air-fuel mixture in an engine can be controlled to realize a so-called ideal air-fuel ratio, i.e., the air-fuel ratio at which complete combustion occurs just prior to misfire, and there is an increase in the exhaust hydrocarbon HC, the concentration of harmful constituents such as carbon monoxide CO and hydrocarbon HC will be minimized, and the concentration of nitrogen oxides NO.sub.x will become less than that occurring when the engine is running in the vicinity of the stoichiometrical air-fuel ratio. The realization of this so-called ideal air-fuel ratio would be extremely advantageous from the viewpoint of counteracting undesirable exhaust emissions, and, from an economical viewpoint, will bring the advantage of a minimum specific fuel consumption.
It is for the above reasons that a suitable method has been sought of detecting the ignition limits of an engine. However, as yet a practical, precise, and reliable method for detecting these ignition limits has not been found.